As such, she was the only person on shift with clearance to access the Ballina centre's medication rooms.

But Ms Haines said one of the locked rooms in the centre's hostel required a pin code to get inside - a number she had not memorised, having only worked a handful of shifts at her new job in May 2014.

"I asked the care workers - they knew the pin,” she said.

The nursing home's other medication rooms required a swipe card with special permission to access - a card given to registered nurses, not care staff.

Ms Haines took the witness stand on Friday for the first time in her trial as defence barrister Troy Edwards began his evidence.

The court previously heard a lightning strike had damaged the centre's swipe key system so, while it would still only grant access to those cards with the correct clearance level, it kept no record of which swipe card had accessed a room.

Ms Haines said she had heard about the lightning strike but did not know the specific details of the damage.

The two women died the day after they had made complaints about Ms Haines.

She recounted the moment former director of care Wendy Turner spoke to her and handed her a sealed envelope containing complaints from Ms Darragh and another resident, Marjorie Patterson.

She said Ms Turner warned her not to have contact with either resident unless a care staff worker accompanied her.

She had been notified of a third pending complaint but was not told it came from Ms Spencer, the trial previously heard.

Speaking in a South African accent, Ms Haines recalled speaking with two care workers, Marlene Ridgeway and Narelle Edwards, shortly after learning about the complaints.

"I said to (Ms Ridgeway) I had been working there just over a week and there had already been two complaints...,” she said.

"She said, 'Look, it will probably just be a reprimand.'

"I felt relieved because it wasn't an issue.”

Ms Haines also described hearing Ms Darragh moan during the night, hours before her death.

"She was like groaning, like she was having a nightmare, and Marlene Ridgeway and I settled her verbally and she stopped groaning and we left the room,” she said.